Can’t Recover the original IMEI patching certificate G920I

Hi! i have a problem, i need to recover an original imei on a G920I the Z3X pro have the option of write imei but when i clic patch certificate the Z3X made all the process but the imei not change.

I have a problem with 2 G920I that someone unlock using a certificate and now the owner wants the original imei.

did you know if is possible?